There may be a case where a user configures partitions of a packet relay apparatus that is provided with a plurality of ports for packet transmission/reception. The packet relay apparatus, for which the partitions are configured, transmits a packet from one port within one of the partitions that includes another port having received the packet. In other words, the packet relay apparatus does not transmit the received packet from a port included in the other partition(s).
For example, now, assume that the plurality of ports is used by two departments, for example, a Department A and a Department B. One partition is configured with respect to the ports that are used by the Department A, and on the other hand, the other partition is configured with respect to the ports that are used by the Department B, in the packet relay apparatus. Upon receipt of a packet, the packet relay apparatus transmits the packet, received by the port used by the Department A, from a port included within the partition for the Department A. In other words, the packet relay apparatus does not transmit the packet from a port included within the partition for the Department B.
A method of forming a Virtual Local Area Network (VLAN) on a physical network has been conventionally known, and packet relay apparatuses that achieve a transparent VLAN network have been studied, as well. Note that the term “transparent VLAN network” means a network capable of relaying packets regardless of values of VLAN information which are set for the packets. In other words, the packet relay apparatus achieving the transparent VLAN network is capable of relaying the packets regardless of the values of the VLAN information. Note that the term “VLAN information” means information for identifying a VLAN to which an apparatus designated as a packet transmission source belongs.
For example, a Q-in-Q technique has been known as one of the techniques achieving the transparent VLAN network. Upon receipt of a packet, a packet relay apparatus, which performs the Q-in-Q technique, attaches a piece of VLAN information that is used within the same apparatus to the packet. In addition, the packet relay apparatus attaches the same VLAN information to all the packets. Then, the received packet is handled, within the same apparatus, as the one for which the same VLAN information is set, by the packet relay apparatus, regardless of the VLAN information set for the received packet, and the packet is transmitted from a port within the partition that includes the port having received the packet. Techniques related to packet queuing have been discussed.
However, the above technique achieving the transparent network has a disadvantage that it is difficult to separately handle the packets with respect to each VLAN. More specifically, the packet relay apparatus, which performs the Q-in-Q technique, handles all of the packets as the ones for which the same VLAN information is set, within the apparatus. In other words, this packet relay apparatus handles the packets as the ones derived from the same VLAN.
The technique hereinafter disclosed is in view of the disadvantage discussed above, and the purpose of the present disclosure is to provide a packet relay apparatus capable of separately handling packets with respect to each VLAN.